I'm planning on doing the work as far as the code goes. Since steemit already supports github flavored markdown, it shouldn't be a hard change. They are using remarkable, which supports highlightjs.
Obviously the programming community isn't the largest on steemit, but I feel it has a great chance to be and this feature would make a huge difference.
That said if the team doesn't want to accept it, I understand.
RE: Adding Syntax Highlighting to Steemit?